Abrasive strip top sharpeners



S pt. 22, 1970 'c. GRAVERSEN 3,529,495

ABRASIVE STRIP TOP SHARPENERS Filed Jan. 30, 1968 v 4 Sheets-Sheet l f *5. FIG. 2

CURTIS L. GRAVERSEN lNVE/VTOR BY BUCKHORM BLORE, KLAROU/ST 8 SPAR/(MAN ATTORNEYS Se t. 22, 1970 c. GRAVERSEN 3,529,495

ABRASIVE STRIP TOP SHARPENERS Filed Jan. 30, 1968 4 Sheets-Sheet :3

FIG. 4

FIGE) CURTIS L. GRAVERSEN INVENTOR BUG/(HORN, BLORE, KLAROU/S 7' a SPAR/(MAN ATTORNEYS Sept. 22, 1 910 4 Sheets-- Sheet &

Filgd Jan. 30, 1968 OQQ CURTIS L. GRAVERSEN INVENTOR BUCKHORN, BLORE, KLARQUIST & SPARKMAN ATTORNEYS United States Patent 3,529,495 ABRASIV E STRIP TOP SHARPENERS Curtis L. Graversen, Milwaukie, 0reg., assiguor to Omark Industries, Inc., Portland, Greg, a corporation of Oregon Filed Jan. 30, 1968, Ser. No. 701,674 Int. Cl. B2311 63/00 US. C]. 7625 23 Claims ABSTRACT OF THE DISCLOSURE A top sharpener (FIGS. 1-7) includes an arm 70 on a sprocket cover 24. The arm 70 carries a supply roll of abrasive strip and guides the strip in an arcuate path for top sharpening a saw chain 42. A braking roll 82 holds the strip against accidental advancement. A resilient pad 92 backs up the strip. An endless belt 262 (FIGS. 8 and 9) of a top sharpener 200 is carried by an arm 206 mounted pivotally on a sprocket cover 220. A top sharpener 300 (FIGS. 10 and 11) includes a cartridge 302 adapted to be pressed downwardly in a guideway 324 in a sprocket cover 326 and carrying an abrasive strip 320. A top sharpener 400 (FIGS. 12-14) includes an arm-like cartridge 402 removably and pivotally mounted by a pin 450 between slotted flanges 456 of a sprocket cover 404 and carrying an abrasive belt 444.

DESCRIPTION This invention relates to improved top sharpeners, and more particularly to abrasive strip top sharpeners.

An object of the invention is to provide new and improved top sharpeners.

Another object of the invention is to provide abrasive strip top sharpeners.

A further object of the invention is to provide chain saws including abrasive strip sharpeners and sprocket guard covers carrying the sharpeners.

Another object of the invention is to provide chain saws having detachable cartridge-type top sharpeners.

Another object of the invention is to provide chain saws each having a sharpener including an arcuate arm holding a strip of abrasive material and adapted to move the strip into contact with top surfaces of a saw chain to sharpen the saw chain.

Another object of the invention is to provide a chain saw having a sharpening arm carried by a sprocket guard cover and carrying a roll of abrasive strip and guiding the strip in an arcuate path for moving the strip into engagement with top surfaces of a saw chain.

Another object of the invention is to provide a chain saw having a cartridge carrying an abrasive strip and slidable along a guideway in a sprocket guard cover to move the strip into engagement with top surfaces of a saw chain.

Another object of the invention is to provide a chain saw having an arm carrying an abrasive strip and also carrying a pivot pin and adapted to be inserted into and removed from a hole in a sprocket guard cover which is provided with slots in cars receiving the pivot pin.

The invention provides top sharpeners for chain saws which include carriers mounted movably on the chain saws for movement from retracted positions to sharpening positions in which abrasive strips are brought into contact with top surfaces of projecting elements of saw chains driven by sprockets of the chain saws. The abrasive strips preferably include initial sharpening portions in sharpening positions and additional portions initially kept in reserve and movable to the sharpening positions when the initial sharpening portions become worn. In a sharpener forming one specific embodiment of the invention, an arm pivotal on a sprocket guard cover carries a supply roll of abrasive strip 3,529,495 Patented Sept. 22, 1970 "ice and guides the strip along an arcuate portion thereof with the forward end portion of the strip projecting out of the cover and with a detented feed roll adapted to push the strip along the arcuate portion. In a sharpener forming an alternate embodiment of the invention, an arm mounted pivotally on a sprocket guard cover carries an endless abrasive belt which is movable to present fresh abrasive surfaces to an arcuate portion of the arm which presses the adjacent portion of the strip against the top surfaces to be ground, of a saw chain. In a sharpener forming an alternate embodiment of the invention, a roll of an abrasive strip is carried in a cartridge which is manually movable from and insertable into a guideway in a sprocket guard cover, and guides the strip from the roll along an arcuate portion adapted to press the strip against the top surfaces of the projecting elements of a saw chain. In a sharpener forming an alternate embodiment of the invention, an arm is insertable into and removable from an opening in the sprocket guard cover and has a pin projecting from opposite sides of the arm and adapted to seat pivotally in ends of slots in guide flanges of the sprocket guard cover, an endless abrasive belt being mounted on the arm.

A complete understanding of the invention may be obtained from the following detailed description of top sharpeners forming specific embodiments thereof, when read in conjunction with the appended drawings, in which:

FIG. 1 is a side elevation view of a chain saw having a top sharpener forming one embodiment of the invention;

FIG. 2 is an enlarged, fragmentary, partially sectional, side elevation view of the top sharpener and chain saw of FIG. 1;

FIG. 3 is an enlarged, vertical sectional view taken along line 33 of FIG. 2;

FIG. 4 is an enlarged, vertical sectional View taken along line 44 of FIG. 2;

FIG. 5 is an enlarged, horizontal sectional view taken along line 55 of FIG. 2;

FIG. 6 is an enlarged, horizontal sectional view taken along line 66 of FIG. 2;

FIG. 7 is an enlarged, vertical sectional view taken along line 77 of FIG. 3;

FIG. 8 is a fragmentary, partially sectional, side elevation view of a chain saw having a top sharpener forming an alternate embodiment of the invention;

FIG. 9 is an enlarged, vertical sectional view taken along line 9-9 of FIG. 8;

FIG. 10 is a fragmentary, partially sectional, side elevation view of a chain saw having a top sharpener forming an alternate embodiment of the invention;

FIG. 11 is an enlarged, horizontal sectional view taken along line 11-11 of FIG. 10;

FIG. 12 is a fragmentary, partially sectional, sile elevation view of a chain saw having a top sharpener forming an alternate embodiment of the invention;

FIG. 13 is an enlarged, fragmentary, vertical sectional view taken along line 1313 of FIG. 12; and

FIG. 14 is an enlarged, fragmentary, vertical sectional view taken along line 1414 of FIG. 12.

Referring now in detail to the drawings, there is shown in FIGS. 1-7 a top sharpener 20 mounted on a cover 24 detachably mounted on studs 26, which are carried by an engine frame 28 of a chain saw 30 and which also mount a saw bor 32. A top sharpening saw chain 34 courses along an endless path defined by the saw bar 32 and a drive sprocket 36 driven by a clutch 38. The sharpener is adapted to sharpen cutter teeth 40 (FIG. 2) of cutter links 42 of the saw chain and to also abrade tips 44 of depth gauges 46 of the cutter links. The cutter teeth are allochiral and have shank portions having kerf side slitting edges 48, and also have steeply sloping top plates 50 having kerf bottom cutting edges 52 and top surfaces 54 adapted to be abraded to top sharpen the cutting edges 52 as the cutter links are advanced over the sprocket 36. The saw chain also includes rivets 56 securing bodies 58 of the cutter links to side links 60 and to center drive links 62 and the center drive links to guard links 64 and some of the side links 60. The cutting edges 52 are located less far rearwardly of the midpoint of an imaginary line joining the two rivets of each cutter link than is the trailing edge of the tip 44 of the depth gauge positioned forwardly of this midpoint. This provides a desired height differential between the cutting edge 52 and the tip of the depth gauge from the sharpening while the cutter link is traveling around an arcuate path such as, for example, the sprocket 36.

A carrier or guide arm (FIGS. 2-6) carries a supply roll '72 of an abrasive strip 74 having a waterproof cloth backing and an abrading face '76 of abrasive particles bonded to the backing by a waterproof adhesive. The roll 72 fits into a cylindrical hole 78 in the arm and the strip extends from the hole and between a braking surface 80 and a resilient braking roll 82 on a detent shaft 84 normally held against rotation by a detent spring 86. The strip extends from the roll 82 along a guideway 88 in the arm 70 having an arcuate portion 90 which is, when the strip is pressed against the saw chain, substantially concentric with the arcuate path followed by the tips 44 of the depth gauges 46 and the sharpening surfaces 52 of the top plates 50. A slightly compressible pad 92 in an arcuate recess 94 in the arm resiliently backs up the portion of the strip engaging the tips of the saw chain to permit the strip to conform substantially exactly to the arcuate path of the tips. The pad 92 comprises an arcuate metal strip or heat sink 95 of high heat conductivity in contact with the back of the strip and a pad member 97 of polyurethane foam material backing up the heat sink 95. The heat sink may be of a metal having high heat conductivity such as, for example, an aluminum alloy. The arcuate portion 90 of'the guideway has overhanging edges 96 retaining the strip in the guideway. The strip travels from the arcuate portion through a straight exit portion 98 (FIG. 2) of the guideway 88 in the free end portion of the arm 70 and the used, outer end portion of the strip may be torn off as desired. When the operatively positioned portion of the strip becomes worn, a fresh, unused portion can be fed to the operative position by inserting a screwdriver (not shown) through a hole 100 (FIG. 3) in the cover 24 and into a screwdriver slot 102 in the shaft 84 and the shaft rotated to turn the roll 82 to advance the strip from the supply roll 72 toward the outer end of the carrier arm 70. The detenting springs 86 permit such deliberate turning of the shaft but hold the shaft and the roll 82 against rotation during sharpening operations. The detent springs fit at the ends thereof into notches or sockets 106 in the arm. Actually, the detent springs are joined together by end portions 108 (FIG. 3) and so are integral with each other.

The arm 70 (FIGS. 3 and 4) has a tubular boss 110 carrying a tube 111 on a cover 113, the tube 111 adapted to normally abut a flange 112 of a flanged tube 114 in the cover 24 when a combined tension and torsion spring 115 pulls the arm 70 to its normal position. The spring is keyed to the tube 114 by a pin 116 and is keyed by a pin 118 to the cover 113. Screws 120 are secured to the tube 114 and the cover 113 to the cover 14 and the arm 20, respectively. The spring 115 normally holds the arm in a retracted position in which the telescoping tubular portion of the cover 113 abuts the flange 112 and the arm 70 is swung counterclockwise from its position shown in FIG. 2 to engagement with the end 122 of a slot 124 in top flange 126 of the cover. In this retracted position of the arm, the arm is out of the plane of the saw bar 32 and saw chain 34, and a shoulder 130 (FIG. 6) prevents movement of the arm into the path of the saw chain. The arm may be moved laterally into the plane of the saw chain and then swung clockwise as viewed in FIG. 2

to bring the abrasive strip into engagement with the tips 44 and the top sharpenable surfaces 52 of the top plates 50. An adjustment screw (FIGS. 2 and 6) screwed through a tapped bore in an ear 142 of the arm 70 limits the depth of cut on the saw chain by engaging a stop 144 on the cover 24. The adjustment screw also provides a handle for manipulation of the arm by an operator.

EMBODIMENT OF FIGS. 8 AND 9 A sharpener 200 forming an alternate embodiment of the invention includes an endless abrasive belt or endless strip 202 traveling around a core 204 of an arm 206 and rollers 208 and 210 carried with the core 204 in a hollow sheet metal arm-like shell 212. The roller 208 is keyed to a shaft 214 journaled in a boss 216 and adapted to fit into a socket 218 in a sprocket cover 220 of a chain saw 222 having an engine having a frame 224 and driving a sprocket 226 through a clutch 22 8 to drive a saw chain 230 like the chain 34. An access hole 232 is provided in the bottom of the socket 218 for insertion of a screwdriver (not shown) for engaging slotted adjacent end of the shaft 214 to turn the roll 208 to advance a fresh portion of the belt to the arcuate operative or sharpening position in which an arcuate pad member 234 like the pad 92 and positioned in arcuate recess 238 in the core 204 supports the strip in concentric relationship to the path of the tip surfaces of the projecting elements of the saw chain to be abraded. A braking roll 240 carried by and keyed to a triangular detenting shaft 242 normally holds the strip against movement. A leaf spring detent 244 normally holds the roll 240 against rotation.

An adjustment screw 250 threaded through a tapped bore in an ear 252 engages a stop 254 of the cover 220 to limit depth of cut, the ear projecting through a slot 256 in top flange 258 of the cover. An open window 260 bounded by arcuate belt retaining flanges 262 is provided in the shell 212 at the operating portion of the belt.

A flange sleeve 270 journaling the roll 210 is detach- I ably secured to the casing 212 by screws 272 and is telescopically mounted for longitudinal and rotational movement on a sleeve portion 274 of the cover 220. A combined tension and torsion spring 276 is secured and keyed by pins 278 and 280 to the sleeve portion 274 and the sleeve 270, respectively. The spring urges the arm 206 normally toward a retracted position in which the arm is swung counterclockwise from its operative position shown in FIG. 8 and to the left as viewed in FIG. 9. In the retracted position, the sleeve 270 abuts bottom 282 of socket 284 of the cover 220.

EMBODIMENT OF FIGS. 10 AND 11 A sharpener forming an alternate embodiment of the invention is a cartridge and includes a case 302 having a cupped body 304 and a cover plate 306 secured thereto by screws 308 screwed into tapped tubular bosses 310. Fixed, partially cylindrical, rolls 312 having arcuate cutouts 314 and arcuate overhanging guide flanges 316 guide an abrasive strip 320 along a path concentric to the paths of tips of a saw chain 322 like the saw chain 34 of FIG. 1 when the sharpener is in the position thereof shown in FIG. 10, the flanges 316 being spaced laterally outside the path of the tips of the saw chain. The case 302 is generally rectangular in transverse cross section and fits closely and slidably in a complementarily shaped guideway 324 in a cover 326 of a chain saw 330 having an engine frame 332, a saw bar 334 and a drive sprocket 336 driven by the engine. A supply roll 338 of the abrasive strip 320 is mounted in the space in the case 302 above the fixed rolls 312, the upper one of which has an arcuate clearance cutout 340. The strip extends from the roll 338 past a braking roll 342 having a triangular detent shaft 344 normally held against rotagifzn by a leaf spring supported in a slot 346 in the roll An adjustment screw 350 screwed through a tapped bore in an ear 352 engages a stop member 354 of the cover 326 to limit the depth of cut. The cartridge may be removed from the chain saw and carried in a pocket of the operator whenever sharpening is not being done. Whenever it is desired to have a fresh, unused portion of the strip, the upper end of the strip is pulled to move the used portion out and the fresh portion into the arcuate, operative portion of the path of the strip. A pad 360 like the pad 92 supports the portion of the strip which engages the saw chain.

EMBODIMENT OF FIGS. 12, 13 AND 14 A sharpener 400 forming an alternate embodiment of the invention includes a pivotal arm-like cartridge 402 which is easily attached to and easily detached from a sprocket cover 404 of a chain saw 406 having an engine having a frame 408 to which are secured a saw bar 410 and the cover 404, which are detachably mounted on studs 412 of the frame 408 by nuts 414. The engine drives a sprocket 416 through a clutch 418 to drive a saw chain 420 like the saw chain 32. The cover 404 is cupped, and has a slot 422 in a top flange 424. The cartridge includes a hollow, shell-like arm 430 made of two sheet metal halves 432 and 434 secured together by screws 436 and hollow nuts 438, which secure a core 440 of tough, low friction plastic material rigidly between the halves 432 and 434. The core and overhanging flanges 442 of the halves 432 and 434 guide an abrasive belt or strip 444 along a curved path having an arcuate portion 446 which is concentric with the outer or tip surfaces of the projecting elements of the saw chain to be abraded, when the cartridge 402 is in the position shown in FIG. 12. The length of the arcuate portion is suflicient to always be in engagement with at least one tip of each of two adjacent cutter links 448 of the saw chain 420.

A pin 450 (FIG. 14) carried by the core extends through close-fitting holes in the two halves 432 and 434 and is adapted to be moved downwardly into upwardly opening slots 454 in upstanding flanges 456 of the cover and then be moved along the slots to the lefthand ends thereof to the position shown in FIG. 12. This mounts the cartridge 402 pivotally on the cover, and when an upstanding handle portion 460 is swung counter clockwise, as viewed in FIG. 12, the arcuate portion 446 of the belt is swung into sharpening engagement with the projecting tips of the saw chain as the chain is driven by the sprocket 416. After the chain is sharpened, the cartridge may be removed from the cover and placed in the pocket of the operator. The belt may be moved, by pushing it manually, to position a fresh portion at the sharpening position. However, there is enough friction that the pull of sharpening does not move the belt. The core 440 has rounded end portions 470 and 472 to guide the strip smoothly. The arm 430 fits closely between the flanges 456 so that frictional engagement therebetween normally holds the arm against movement while permitting easy movement when the handle 460 is moved.

The above-described sharpeners use inexpensive, highly effective, abrasive strip, which can be thrown away after being worn out, and which require no dressing movement. The cartridges can be easily assembled with and easily detached from the chain saws and are compact and easily stored.

It is to be understood that the above-described arrangements are simply illustrative of the application of the principles of the invention. Numerous other arrangements may be radily devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof.

What is claimed is:

1. In a abrasive strip top sharpener for a chain saw including a top sharpenable saw chain and means for advancing the saw chain along an arcuate path,

a flexible, abrasive strip means,

carrier means carrying the strip and including a guide portion supporting a portion of the strip,

the carrier means serving to mount the strip means for movement along the guide portion,

and mounting means mounting the carrier means on the chain saw for movement between a retracted position in which the abrasive strip is entirely out of contact with the saw chain and a sharpening position in which the portion of the strip supported by the guide portion of the strip engages the top surfaces to be ground of the saw chain.

2. The abrasive strip sharpener of claim 1 wherein the carrier means includes feed means normally holding the strip against movement during sharpening and selectively operable to permit advancement of the strip along the carrier means.

3. The abrasive strip sharpener of claim 2 wherein the feed means includes a manually operable detented feed roll engaging the strip.

4. The abrasive strip top sharpener of claim 1 wherein the abrasive strip is in endless belt form.

5. The abrasive strip top sharpener of claim 1 wherein a supply portion of the strip is in roll form and the carrier means includes a receptacle portion for retaining the supply portion of the strip.

*6. The abrasive strip top sharpener of claim 5 including a sprocket guard cover and wherein the carrier means comprises an arm pivotally mounted on the sprocket guard cover.

7. The abrasive strip top sharpener of claim 6 wherein the carrier means includes an adjustment screw adapted to engage a stop on the sprocket guard cover.

8. The abrasive strip top sharpener of claim 6 wherein the sprocket guard cover has a top flange provided with an opening and the arm has a handle portion projecting through the opening.

9. The abrasive strip top sharpener of claim 1 wherein the guide portion of the carrier means is arcuate and is adapted to support a portion of the abrasive strip in a position engaging the saw chain and centered on the sprocket.

10. The abrasive strip top sharpener of claim 9 wherein the guide portion of the carrier means includes resilient backing means supporting the abrasive strip.

11. The abrasive strip top sharpener of claim 10 wherein the resilient backing means includes a non-resilient backing plate engaging the abrasive strip and a resilient pad supporting the backing plate.

12. The abrasive strip top sharpener of claim 1 wherein the abrasive strip is in the form of an endless belt.

13. The abrasive strip top sharpener of claim 12 wherein the carrier means comprises an arm mounting the abrasive strip, and frame means mounting the arm means pivotally relative to the path of the saw chain.

14. The abrasive strip top sharpener of claim 1 including a sprocket guard cover having a top flange having an opening therein and bracket means having slots therein projecting from the top flange, the carrier means comprising an arm adapted to be inserted into the opening and having a pin adapted to fit pivotally into the slots to mount the arm pivotally on the cover.

15. The abrasive strip top sharpener of claim 1 including a sprocket guard cover having a flange having an opening therethrough and a guideway extending from the opening, the carrier means comprising a cartridge insertable in and slidable along the guideway.

16. The abrasive strip top sharpener of claim 15 wherein the cover and the cartridge include adjustable stop means adapted to limit the extent to which the cartridge can be inserted into the cover.

17. In a top sharpener for a chain saw including frame means, a top sharpenable saw chain and means on the 7 frame means for advancing the saw chain along an arcuate path,

a sharpening member, unitary carrier means carrying the sharpening member portion supporting a portion of the strip, and mounting means on the frame means defining a guideway detachably receiving the carrier means and mounting the carrier means for movement between the carrier means and a retracted position in which the sharpening member is entirely out of contact with the saw chain and a sharpening position in which the sharpening member engages the top surfaces to be ground of the portion of the saw chain in said arcuate p the carrier means being insertable into and removable from the mounting means as a unit. 18. The top sharpener of claim 17 wherein the sharpening member is an abrasive strip.

19. The top sharpener of claim 18 wherein the abrasive strip is in roll form.

20. The top sharpener of claim 18 wherein the abrasive strip is in endless belt form.

21. The top sharpener of claim 17 wherein the carrier means is a cartridge and the guide means comprises a socket in the frame means extending toward said arcuate path and enabling the cartridge to be inserted into the socket and withdrawn completely therefrom.

22. In a cartridge for a top sharpener for a chain saw,

a housing portion having parallel guide surfaces at sides thereof and also having a forward end,

and an abrasive member carried by the housing portion and having an arcuate abrading surface positioned at the forward end of the housing portion.

23. The cartridge of claim 22 wherein the abrasive member is a roll of an abrasive strip and the housing portion includes means mounting the roll therein and also includes arcuate guide means at the forward end guiding the strip in an arcuate path.

References Cited UNITED STATES PATENTS 2,835,086 5/1958 Longmire et al. 51-361 XR 3,147,644 9/1964 Oehrli 7637 3,435,860 4/1969 Silyon 14332 BERNARD STICKNEY, Primary Examiner US. Cl. X.R. 51-361; 14332 

